In new construction, whether commercial, residential, or industrial, it is often necessary to extend a pipe or conduit (water, gas, electrical, etc.) through a wall or a floor. Furthermore, it is frequently desirable or even mandatory to provide a hydrostatic seal around the pipe or conduit to preclude seepage of water or other fluids through the wall or floor. The most practical and effective seal construction for applications of this kind, in most instances, is an expansion seal formed of a series of interleaved blocks of rubber or other elastomer interconnected by a sequence of pressure plates, with a plurality of bolts extending between the pressure plates; the bolts are tightened to squeeze the elastomer blocks between the pressure plates, expanding the blocks to form a continuous hydrostatic seal around the periphery of the pipe. A preferred construction for a wall seal closure of this kind is described and claimed in U.S. Pat. No. 3,528,668 of Bruce G. Barton. Other wall closure seal constructions for forming peripheral seals on pipes and conduits are also known in the art.
To assure an effective seal, in applications of this kind, it is highly desirable and often necessary to form an opening in the wall or floor, through which the pipe or conduit can extend, with an internal diameter large enough to afford an essentially symmetrical annular space between the pipe and the opening. The diameter of the wall opening may vary to a substantial extent, depending upon the outside diameter of the pipe or conduit and the particular seal to be used. Thus, the internal diameter required for the wall opening may range from just under two inches up to two feet or more. For most construction of this kind, particularly in a concrete wall, a wall sleeve extending through the concrete form is employed. Accuracy of location of the wall sleeve is an important consideration. Another potentially critical requirement, in many applications, is the prevention of water seepage between the opposite sides of the wall along the outer surface of the wall sleeve.
One practical and effective wall sleeve construction that has seen widespread use in applications of this kind is a metal tube having a length equal to the width of the wall and having a metal ring welded to the outside central portion of the metal sleeve. The metal ring serves as a water stop to preclude water seepage along the outer surface of the sleeve, at the interface between the sleeve and the concrete wall. The ring also serves as an anchor to preclude axial movement of the wall sleeve relative to the wall. This metal sleeve construction, however, presents difficult technical problems of a continuing nature.
Thus, it is quite difficult to mount the conventional metal wall sleeve in a concrete form in a manner that provides accurate location of the sleeve and that also prevents entry of concrete or debris into the sleeve. Even relatively minor variations in spacing between the concrete form panels, in the region adjacent the wall sleeve, may allow entry of concrete into the sleeve or may require dismantling an erected form to shorten the sleeve. Various arrangements have been proposed to overcome these mounting and contamination difficulties, usually involving flanges of one kind or another on the ends of the metal sleeves. However, these expedients add materially to the costs of the metal wall sleeves, which are expensive to begin with. It is also rather impractical to maintain an inventory of sleeves in stock; the wide variations in wall width and in required sleeve diameter produce too many combinations for economical storage. Further, corrosion is a continuing problem.
Another substantial problem in the use of metal wall sleeves, which are often made of steel, results from the weight of the sleeve. For small diameter steel wall sleeves, this is not a major problem. For larger sleeves however, the weight of the sleeve becomes an important factor; secure mounting of the sleeve in a concrete form, so that it will not be dislodged when the concrete is poured, becomes quite difficult. Larger sleeve sizes may also require the services of two men for installation in the form, adding to the applicable labor cost.